1. Field of the Invention
The present invention relates to a substrate structure using a so-called carbon nano tube (CNT), a carbon nano fiber (CNF) or the like being a linear structure made of carbon elements and a manufacturing method of the same.
2. Description of the Related Art
A CNT and a CNF which are linear structures of carbon-based self-organizing materials, in particular the CNT, attract attention because of their many appealing physical properties.
Because of a superior property of having a low electric resistance and a high mechanical intensity, the CNT is expected to be applied to a wide range of fields such as a semiconductor device represented by an LSI, a variety of sensors such as an acceleration sensor, an electronic device, and a heat-radiating device.
[Patent Document 1] Japanese Patent Application Laid-open No. 2005-145743
[Patent Document 2] Japanese Patent Application Laid-open No. 2006-255817
In order to grow the CNTs in high density and without unevenness, it is necessary that catalytic metals to be nucleuses (staring points) of CNT growth exist in high density and independently. Thus, a technology is developed to deposit the catalytic metals in a form of fine particles on a base thin film. However, if catalytic fine particles are deposited in such a manner, aggregation of the catalytic particles occurs when a growth temperature of the CNT is reached. A concrete example is shown in FIGS. 7A and 7B. In this case, aggregates 103 of the catalytic particles of various sizes randomly exist on a base thin film 102 on a silicone substrate 101 and initial fine particle forms are not maintained, so that a density of the catalytic fine particles is decreased (FIG. 7A). Since a diameter of the CNT is specified by a size of the catalytic particle, CNTs 104 are formed uneven in forming location and diameter (FIG. 7B), and so there is a problem that a dense growth of the CNTs is difficult.
For example, in Patent Document 1, there is disclosed a technology in which a catalytic metal layer is formed on an aluminum layer being a base thin film and then fine particles including the catalytic metals are formed by a heat treatment. In this method, it is difficult to control forms of the fine particles as desired, and therefore a decreased density of the catalytic particles is brought about similarly to in the above-described case.